An internal combustion engine of this type is disclosed for example in Japanese unexamined Patent Publication No. 59-29733.
With this engine, the injection end timing for fuel injection using fuel injection valves for each cylinder is timed to occur just before the intake stroke for each cylinder. This is achieved by variably setting the injection start timing which is calculated backwards for a fuel injection quantity (fuel injection time) computed on the basis of the engine operating conditions. As a result, high combustion stability can be achieved.
Engine intake flow however is influenced by engine operating conditions prior to the intake stroke due to an intake filling effect caused by intake/exhaust valve overlap, and in the case of an engine with variable valve timing, there is also an influence due to valve timing variation.
Consequently, with an allocated injection end timing adapted for steady state conditions, control to give an optimum injection end timing under all operating conditions including transient operation is not possible, so that stable optimum combustion for all operating conditions cannot be attained.
It is an object of the present invention to address the above problem, and improve engine combustion by providing an apparatus and method of injection timing control whereby an optimum injection end timing for all operating conditions including transient operation can be set by detection of the intake flow velocity near the jet of the fuel injection valve.
It is also an object to be able to complete fuel injection at a crank angle position wherein the intake flow velocity near the jet of the fuel injection valve is at a maximum.
Furthermore, it is an object to be able to stably control injection end timing by limiting a variable range of the injection end timing.
Moreover, when a variable valve timing mechanism is provided, it is an object to be able to avoid influence from variations in valve timing on the accuracy of detecting the intake flow velocity near the jet.
It is an even further object to be able to accurately determine the intake flow velocity near the jet of the fuel injection valve.